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Charging-discharging characteristics of macro-encapsulated phase change materials in an active thermal energy storage system for a solar drying kiln

The present study explores suitability of two phase change materials (PCM) for development of an active thermal storage system for a solar drying kiln by studying their melting and solidification behaviors. A double glass glazing prototype solar kiln was used in the study. The storage system consisted of a water storage tank with PCMs placed inside the water in HDPE containers. The water in the tank was heated with help of solar energy using an evacuated tube collector (ETC) array. The melting and solidification temperature curves of PCMs were obtained by charging and discharging the water tank. The study illustrated the utility of the PCMs in using the stored thermal energy during their discharge to enhance the temperature inside the kiln. The rate of temperature reduction was found to be higher for paraffin wax as compared to a fatty acid based PCM. The water temperature during the discharge of the PCMs showed dependence on the discharge characteristics of each PCM suggesting their suitability in designing active thermal storage systems.
PAPER REVISED: 2015-11-09
PAPER ACCEPTED: 2015-12-21
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